The invention relates to a method and an apparatus for current and temperature measurement in an electronic power circuit using parasitic components of the circuit.
The main representatives of electronic power circuits are three-phase converter circuits, whose core components are phase chips, known as half-bridges. Regulating the currents in the load which is connected to the converter usually requires a measurement in the phase outputs or in the positive or negative intermediate circuit. The measurement in the individual power switches, e.g., IGBTs, MOSFETs, diodes, thyristors, etc., is frequently and usually used only to protect against overcurrents. For this, the level of accuracy is permitted to be significantly worse than the accuracy for the measurement for regulating the currents.
For current measurement in electronic power circuits, precise shunt resistors, Hall sensors, magneto resistive sensors or similar current sensors have been usual to date. In these cases, an additional precise sensor component has had to be incorporated into the circuit. Such sensors are relatively expensive on account of the precision and require additional complexity for incorporation. In addition, they require evaluation electronics and, in the case of shunts, also potential isolators in the electronics.
It goes without saying that the need for current or temperature measurement exists not only for the three-phase converter circuits described by way of example above but also for other types of electronic power circuits or power semiconductor modules.
For these and other reasons, there is a need for the present invention.